Cryptographic Wiretappingat 100 Megabits
Charles J. Antonelli, Asst. DirectorCenter for Information Technology IntegrationThe University of MichiganAnn Arbor
2 April 2002
Project Goals
Complete long-term storage of network traffic Cryptographically secured Evidentiary purposes Rapid response to intrusion incident
Problem Space
Systems engineering Cryptographic organization Terabyte storage technologies Legal and regulatory constraints
Systems Engineering
866 Mhz Pentium III CPU (× 2) 528 MB/s PCI (66 Mhz × 64 wide) Ultra-160 SCSI
30 MB/s SCSI disk 15 MB/s SCSI tape
Architecture Storage hierarchy
16 MB segments 1 GB volumes 100 GB tapes
Software pipeline listener creates segments encrypter fills volumes archiver fills tapes Scripts drive pipeline
Cryptographic Organization
Three encryption formats Open header
Translated headers, encrypted payloads Conversation (default)
Encrypted packets Retrieve by src/dst pair
Endpoint Encrypted packets Retrieve by src or dst endpoint
Cryptographic Organization
Three encryption formats Security
Translation security vs. traffic analysis Performance
Translation open to spoofing attack Retrieval
Retrieve when only one endpoint is known
Cryptographic Organization
volume symmetric key(KV)
master public key
translation table symmetric key(KT)master public key
translation tables
KT
Cryptographic Organization
Open Header
Conversation
EndpointKC
Header, payloadKC
KT
Header, payloadKCKC KC
KCKTKDKS
translated header packet payloadconversation key(KC)
Terabyte Storage Technologies
Leverage Moore’s law Start small
LTO w/ library 15 MB/s (13 MB/s), 100 GB/tape 10 Mbps: 1 or 2 tapes/day, every day
Grow large 100 Mbps: 10-15 tapes/day 1 Gbps: 100-150
Terabyte Storage TechnologiesType Adv
MB/sMeasMB/s
GB/volnative
$/GB cc/GB
AIT2 6 50 1.50 1.9
DLT 8000 6 4.6 40 1.40 7.0
Mammoth2
12 9.6 60 1.50 1.5
AIT3 12 100 1.29 0.95
LTO 15 13 100 1.15 2.3
Super DLT 110 1.05 2.6
DVD-R 2.76 4.7/9.4 0.47-0.63
3.2/1.6
EIDE 17-35
163 1.57 2.38
Results
APV running at CITI Fully meets requirements on 100
Mbps network Conversation format
Four week sample 200 GB (two tapes)
Results –Performance Extrema
Packet Size
Max input (observed)
Max input (calc)
Max output (calc)
60 bytes 44 Mbps(92K pps)
68 Mbps(142K pps)
65 Mbps(135K pps)
Synthetic observed
70 Mbps(39K pps)
83 Mbps(46K pps)
93 Mbps(52K pps)
1514 93 Mbps(8K pps)
94 Mbps(8K pps)
104 Mbps(9K pps)
Evidence Handling
Rules for evidence gathering Scene “frozen” Continuity of evidence
Authenticated volume contents Second factor might prove useful
Auditable procedures Open source
Legal and Regulatory Issues Carrier-transport/ECPA Student information/FERPA Privacy/First amendment Human subject guidelines Ownership/copyright Right to know/FOIA Discovery/evidence Search and seizure/Fourth amendment Civil liability HIPAA
Previous Work
Prototype (1998) 166 Mhz Pentium machines (x2) Private 100 Mbps network CD-ROM storage
10 Mbps Vault (2001) OpenBSD (no SMP)
Current Work
100 Mbps APV Flexible crypto policies
Site-specific customization Loss-free degradation
Data integrity Data recovery
Future Work
1000 Mbps APV Cooperating APVs
Round-robin, packet content
Integrity vault Additional requirements?
Non-IP traffic? Network speeds? Retrieval modes? Contacts needed!
Deliverables
Source code Operations Guide Research Report Live statistics
http://www.citi.umich.edu/projects/apv